Spinel is a mineral of very diverse colors. The most common colors are red and pink. In ancient times, red spinels, rubies and pyropes did not differ from each other, calling them in one word - "carbuncle". The best samples of spinel are classified as precious stones.
You can see spinel stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category |
|
Formula (repeating unit) |
MgAl2O4 |
Strunz classification | 4.BB.05 |
Crystal system | Cubic |
Crystal class | Hextetrahedral (43m) H–M symbol: (43m) |
Space group | F 4 3 m (No. 216) |
Unit cell | a = 8.0898(9) Å; Z = 8 |
Identification | |
Color | Various; red, pink, blue, lavender/violet, dark green, brown, black, colourless |
Crystal habit | Octehedra or flat triangular plates caused by twinning |
Twinning | common |
Cleavage | None |
Fracture | Conchoidal |
Mohs scale hardness | 7.5–8.0 |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent to opaque |
Specific gravity | (Depending on the composition) The rare Zn-rich spinel can be as high as 4.40, otherwise it averages from 3.58 to 3.61. |
Optical properties | Isotropic |
Refractive index | 1.719 |
Pleochroism | Absent |
Solubility | None |
Other characteristics | Weak to medium magnetic, sometimes fluorescent (red synthetic yes, natural red sometimes) |